The results

Key headline results and outcomes of the Regenerative Twin

The headline results

84% reduction in whole life carbon
66% reduction in upfront embodied carbon
45% reduction in annual energy consumption
Whole life cost was 95% of the original scheme (capex uplift repaid in 11 years)
Timber products could be responsibly sourced from existing Welsh forests
Correlation between the use of renewable materials and socio-economic benefits
90% reduction in water consumption from the manufacturer of the materials used in the design

Final specification highlights

Two final designs - a like-for-like massing, and a ‘blue sky’ option (radical re-design)
Cross laminated timber (CLT) walls and upper floors - European source for like-for-like, local source for blue sky option - requires supply chain transformation locally
Reclaimed masonry novel sub-structure, with a glulam and CLT suspended floor with sheep's wool insulation between timber i-beam reinforcing joists
Charred timber façade with sheep's wool or hemp insulation
100% recycled plasterboard
Blue roof for rainwater attenuation (based on climate adaptation risk modelling)
No photovoltaic panels installed at handover - planned for 20 years once sufficient carbon budget available

How a regenerative approach affects…

How we mitigate climate changeWhen seen through the lens of climate change mitigation, a regenerative approach shows that greater gains are available than previously thought, by introducing a goal for nature and people to thrive rather than simply reducing carbon emissions.

How we value risk InsurabilityIn collaboration with insurance market stakeholders, we modelled three future loss scenarios, due to water damage, mould and fire damage respectively.A regenerative approach without insurance market engagement increases the risk profile of the project to the market. However, with early engagement and mitigation measures in place, it is possible to significantly reduce the cost of reinstatement if something goes wrong, helping insurers improve the sustainability of their portfolio. For example, we identified these mitigation measures:

Focusing on material resilience over lowest up front impact,

Following the Mass Timber Insurance Playbook principles for all natural materials,

Early installation of leak detection and cavity ventilation monitoring,

Layered building design, where each material can be taken apart section by section and reinstated, and

Procuring local materials.

Climate risk modelling To assess the physical and transitional risks of the changing climate on the site in Wales, the team collectively brainstormed and prioritised risks, identifying the following with the greatest likelihood and severity:

Insurability – which led to the extended market engagement

Increased temperatures and heatwaves – which resulted in additional overheating analysis

Mass migration – The Institute for Economics and Peace, an international thinktank, has predicted that by 2050, 1.2 billion people could be displaced globally due to climate change – and therefore we considered future change of use or extension, and additional community use.

How we understand Social ValueSocial Value does not only consist of the private sector’s obligations under the Social Value Act, but also how the built environment benefits communities, both in the supply chains that provide materials and labour to construct it, and also how it serves a place over its operational life. The following outcomes were specifically identified as a result of the regenerative design choices made on the project:

Community Investment – additional asset uses, community ownership model

Employment – new jobs, new industry, new related business, new skills

Education – improved learning environment, innovative approaches, understanding of ‘green’ skills, increased critical thinking faculty

Health – physical and mental health improvements, social inclusion, improved air quality, increased access to nature

Natural resources – increased biodiversity, use of local timber, regenerative materials – low or no carbon impact, accessible growing spaces

How we communicate with future generations

An unexpected outcome of the Regenerative Twin project was the creation of Sitka, the Amazing Timber Tree children’s book.

The book shares the story of Sitka the Spruce, as he makes the journey from the forest into the classroom and beyond, promoting to young learners that timber can provide society with a positive and regenerative resource. 

We worked in partnership with organisation Tales from Mother Earth, who write and illustrate informative stories for young children to re-engage with the natural world. This enables them to find out more about habitat preservation, biodiversity and the things they can do to act on climate change. The book also includes activities, such as fun facts, crosswords and colouring in pages.

The book was launched on World Environment Day in 2024 and has been shared across numerous children’s classrooms.

Unfinished tales

The Regenerative Twin project challenged the way we currently measure the impact a project is having, both positive and negative.

Because of this, a number of metrics were either not achieved or not quantified, and therefore require further exploration. They included:

Not achieved

Reducing the land consumption of renewable products. For example the material specification consumed a forested area of 46x the Gross Internal Floor Area (GIFA), which was 50% higher than our target which was 30x GIFA.

Whole life carbon including circularity benefits remained above zero, despite all efforts to balance carbon storage with carbon emissions over the life of the building.

Water consumption associated with material manufacture, which despite significant reductions still takes up more than 60% of our 60-year allowance.

Not measured

Natural capital and social outcomes

The increase or decrease in access to nature

The economic value from mainstreaming novel nature-based or regenerative materials

Embodied social value

In addition, a clear next step is the simplification of metrics and indicators to enable the mainstream construction market to engage with regenerative principles.

If we keep doing the same things, we’ll keep getting the same results!How can we do things differently?

Procurement… bring all stakeholders together including the community as soon as possible

Partisanism… establish behaviours and an agreed purpose / vision before RIBA Stage 2.

Short-termism… be open to a longer-term value proposition

How we value risk… engage with the insurance market early, and conduct future climate risk analysis

How we value the supply chain’s role as agents for change… engage with the supply chain early

Detachment of social and environmental outcomes… have a plan to ensure a just (fair and inclusive) transition to a more regenerative outcome